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PSG COLLEGE OF TECHNOLOGY, COIMBATORE - 641 004

SEMESTER EXAMINATIONS, MAY 2008

MTech In!"#$%&!n Techn!'!()Se#e*%e"+2

06NN24 MOBILE COMPTING

Te+ H!."* M$/.# M$"*+ 60

INSTRCTIONS+

1. Answer ALLquestions from PART - A and Answer any 4 questions from PART -.

PART - A M$"* + 10 / 2 20

1. A city has an area of 1600 square miles and is covered by a cellular system that usessquare cells and has a reuse factor of 5. Each cell has a side length of miles and thecity is allocated 50 !"# of s$ectrum %ith channel band%idth of 50 &"# and %ithallocation of 10 control channels $er cell. 'a( )etermine the number of cells in the servicearea. 'b( )etermine the number of voice channels $er cell

2. *tate the attachment $rocedure follo%ed for a mobile station in +,-*

3. rief about the use of the gate/ee$er node in oice over , $rotocol

. "o% the device roaming in handled in ),)

5. 4ist out the consideration to be follo%ed in develo$ing %ireless a$$lications

6. *tate the life cycle of !), a$$lication

7. "o% to you com$are the t%o cases beacon interval of 200ms and A! %indo% of 50msversus beacon interval of 100ms and A! %indo% of 25ms

. om$are the overhead introduced by ",E-4A8 and luetooth medium accessschemes and the resulting $erformance at #ero load9 light load and high load of themedium

:. ;hy has a scri$ting language been added to ;!4 "o% can this language hel$ savingband%idth and reducing delay

10. ;hat is the use of a ect in A*,

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PART - B M$"* + 4 / 10 40

11. a( onsider t%o different cellular systems that share the follo%ing characteristics. he

frequency bands are 25 to 5 !"# for mobile unit transmission and 70 to :0!"# for base station transmission. A du$le? circuit consists of one 30 &"# channel ineach direction. he systems are distinguished by the reuse factor9 %hich is and 7res$ectively. *u$$ose that in each of the systems9 the cluster of cells is du$licated 16times. or soft%are develo$ment com$any %iththe res$onsibility of redesigning their o$erating system such that an a$$lication$rovides the bestB service to the user de$ending on the quantity of availableresources on a %ireless device. om$are and contrast the available o$erating*ystems ,alm =* and ;indo%s E. E?$lain the necessary basic considerations anddifferent ty$es of communication mechanisms available on the o$erating systems andthe required structuring of a$$lication $rograms to ta/e advantage of the ne%functionalities $rovided by the =* '5(

b( Assume you are administering a mobile )!*. Cour database contains 1: $ages.

,ages1@ are accessed very frequently9 $ages 5@7 are accessed some%hat

frequently9 and $ages @1: are accessed rarely. )escribe ho% effectively data can beaccessed by the mobile devices %ith res$ect to the different techniques available formobile data access '5(

1. a( An infrastructure net%or/ using a 1 !bDs EEE 02.11 has 2 nodes 819 and 82connecting to an access $oint A,. At time 09 there is no ongoing transmission. Attimes 10 s9 0s and 60s9 a ne% $ac/et arrives at 819 829 and 819 res$ectively9 to besent to A,. Assume that the random number generator 'for bac/@off( %ill give thefollo%ing values for 81Fs first $ac/et 19 2G for 81Fs second $ac/et 19 3G for 82 19 Gassume that the bac/@off counter is used even for the very first transmission attem$tand that if a node does not start receiving an A& %ithin 2H*

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or fragmentation9 and that all data $ac/ets have the same length of 125 bytes andthat the A& $ac/et has length 25 bytes '5(

b(Assume that t%o devices A and have been connected %ith a luetooth lin/. Cou%ant to su$$ort t%o lin/s bet%een the t%o devices a voice channel of 6 &b$s and anasymmetric data channel. Assuming that you %ant to ma?imi#e the data rate in onedirection9 identify and e?$lain the $ac/et ty$es you must select for the above /inds oftraffic and the data rates on the for%ard and reverse lin/s of the data channel. hema?imum $ayload length in bytes for different $ac/et ty$es are as follo%s )!1 179)"1 279 )!3 1219 )"3 139 )!5 229 )"5 33:9 "1 109 "2 209 "3 309 )10I:). Cou may assume that "19 "29 and "3 $ac/ets are transmitted onceevery t%o slots9 four slots9 and si? slots9 res$ectively '5(

15. a( ;rite a ;!4 $rogram and the associated scri$t file to dis$lay the calendar for the

month of 8ovember 2006 '5(

b( ;hat is the difference bet%een client side $rocessing and server side $rocessingE?$lain %ith neat diagrams. ;rite a $rogramme to call a $rocedure using *cri$t inA*, '5(

DE8)D

TYPE INITIAL3S OF PERSON TYPE 5

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